docs: def get_dataset_url(self, tournament=1):
          """Fetch url of the current dataset.
  
          Args:
              tournament (int, optional): ID of the tournament, defaults to 1
  
          Returns:
              str: url of the current dataset
  
          Example:
              >>> NumerAPI().get_dataset_url()
              https://numerai-datasets.s3.amazonaws.com/t1/104/numerai_datasets.zip?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIYNVLTPMU6QILOHA%2F20180424%2Fus-west-1%2Fs3%2Faws4_request&X-Amz-Date=20180424T084911Z&X-Amz-Expires=900&X-Amz-SignedHeaders=host&X-Amz-Signature=83863db44689c9907da6d3c8ac28160cd5e2d17aa90f12c7eee6811810e4b8d3
          """
          query = """
              query($tournament: Int!) {
                  dataset(tournament: $tournament)
              }"""
          arguments = {'tournament': tournament}
          url = self.raw_query(query, arguments)['data']['dataset']
          return url